Polyurethane production remains one of the most environmentally challenging manufacturing processes in industrial polymerization. Formed from addition reactions of di-isocyanates and polyols, polyurethanes may have a significant embedded environmental footprint because of the challenges associated with both feedstocks. Polyols are themselves polymerization derivatives which use propylene oxide as raw materials. Traditionally, propylene oxide (PO) may be synthesized from a chlorinated intermediate, propylene chlorohydrin.
Ethylene oxide may be one of the important raw materials used in large-scale chemical production. Most ethylene oxide may be used for synthesis of ethylene glycols, including diethylene glycol and triethylene glycol, that may account for up to 75% of global consumption. Other important products may include ethylene glycol ethers, ethanolamines and ethoxylates. Among glycols, ethylene glycol may be used as antifreeze, in the production of polyester and polyethylene terephthalate (PET—raw material for plastic bottles), liquid coolants and solvents.
However, an environmentally acceptable process for the economic production of propylene oxide and ethylene oxide remains elusive. High costs of chlorine and significant waste water production (approximately 40 tons of waste water per tone of PO) has caused manufacturers to look for process options with reduced environmental and safety risks.